--- a/testing/talos/talos/pageloader/chrome/pageloader.js
+++ b/testing/talos/talos/pageloader/chrome/pageloader.js
@@ -233,17 +233,22 @@ function plInit() {
           content.selectedBrowser.messageManager.loadFrameScript("chrome://pageloader/content/lh_dummy.js", false, true);
 
         }
         content.selectedBrowser.messageManager.loadFrameScript("chrome://pageloader/content/talos-content.js", false);
         content.selectedBrowser.messageManager.loadFrameScript("chrome://talos-powers-content/content/TalosContentProfiler.js", false, true);
         content.selectedBrowser.messageManager.loadFrameScript("chrome://pageloader/content/tscroll.js", false, true);
         content.selectedBrowser.messageManager.loadFrameScript("chrome://pageloader/content/Profiler.js", false, true);
 
-        setTimeout(plLoadPage, 100);
+        // Ensure that any webextensions that need to do setup have a chance
+        // to do so. e.g. the 'tps' talos test registers a about:tabswitch
+        // handler during initialization, and if we don't wait for that, then
+        // attempting to load that URL will result in an error and hang the
+        // test.
+        setTimeout(plLoadPage, 2000);
       }, 500);
     };
 
     browserWindow.addEventListener("load", browserLoadFunc, true);
   } catch (e) {
     dumpLine("pageloader exception: " + e);
     plStop(true);
   }